Enable platform echo cancellation through the AudioRecord path.

media/audio/android/audio_record_input.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_AUDIO_ANDROID_AUDIO_RECORD_INPUT_H_
 #define MEDIA_AUDIO_ANDROID_AUDIO_RECORD_INPUT_H_
 
 #include "base/android/jni_android.h"
 #include "base/threading/thread_checker.h"
 #include "media/audio/audio_io.h"
 #include "media/audio/audio_parameters.h"
 
 namespace media {
 
 class AudioManagerAndroid;
 
 // Implements PCM audio input support for Android using the Java AudioRecord
 // interface. Most of the work is done by its Java counterpart in
 // AudioRecordInput.java. This class is created and lives on the Audio Manager
 // thread but recorded audio buffers are delivered on a thread managed by
 // the Java class.
+//
+// The Java class makes use of AudioEffect features which are first available
+// in Jelly Bean. It should not be instantiated running against earlier SDKs.
 class MEDIA_EXPORT AudioRecordInputStream : public AudioInputStream {
  public:
   AudioRecordInputStream(AudioManagerAndroid* manager,
                          const AudioParameters& params);
 
   virtual ~AudioRecordInputStream();
 
   // Implementation of AudioInputStream.
   virtual bool Open() OVERRIDE;
   virtual void Start(AudioInputCallback* callback) OVERRIDE;
@@ skipping 28 matching lines @@
 
   // Owned by j_audio_record_.
   uint8* direct_buffer_address_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioRecordInputStream);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_ANDROID_AUDIO_RECORD_INPUT_H_